This research will examine growth of normal human marrow in a compact cell culture "OXYCELL" bioreactor. This bioreactor is suited for experimental manipulation due to its small cell volume and in-house manufacture. This research will examine the benefit of providing an adherent substrate in the bioreactor for stromal cell attachment and growth. Two distinct substrate choices, polysulfone ultrafiltration membrane and "OPTICELL" ceramic matrix, will be tested and compared. Hematopoietic lineages culture will be quantified to assess performance differences. The second part of the proposal deals with the seeking of CD34+ progenitor cells into a bioreactor in which an established stromal cell microenvironment is compartmentalized within a 0.2 uM microfiltration membrane. The progenitor cells will share cell space medium with the adherent cells but will not be in direct cell-cell contact. Growth will be compared to cells seeded directly into the microenvironment space and into a bioreactor without an established microenvironment. Exogenous growth factors will be tested for impact on the growth of progenitor cells seeded into the bioreactors. Cultured cells will be phenotyped for lineage commitment and differentiative stage and assayed for uncommitted and committed progenitors. This work is to develop a bioreactor suited for bone marrow culture applications. The bioreactor is to be incorporated into a cultureware to be supported by an automated cell culture instrument (currently under development) designed specifically for clinical use in immunotherapy.